Barrier movement operators are automated systems which are used to move a barrier with respect to an opening. Examples of the barriers to be moved include garage doors, gates, fire doors and rolling shutters. The primary examples herein involve garage door operators but the principles described and claimed therein relate to all barrier movement operators. A number of barrier movement operators have been sold over the years most of which include a head unit containing a motor connected to a transmission. The transmission, which may include, for example, a belt drive, a chain drive, a screw drive or extendible arm is then coupled to the barrier for opening and closing.
Such barrier movement operators also typically include a wall control unit, which is connected to send signals to the head unit thereby causing the head unit to open and close the barrier. In addition, these operators often include a receiver unit at the head unit to receive wireless transmissions from a hand-held code transmitter or from a keypad transmitter, which maybe affixed to the outside of the area closed by the barrier or other structure.
As barrier movement operators open and close the barriers, the barrier may come into contact with an obstruction. Previous systems have allowed the barrier operator systems to determine if an obstruction has been encountered and to either stop or reverse the direction of the travel of the barrier once this determination has been made. For instance, some previous systems measured the force applied to the barrier by the motor. The systems then compared the measured force to an expected value plus a fixed cushion value. If the comparison indicated that the measurement value exceeded the expected value plus the cushion value (together, a threshold value), then the downward barrier movement was reversed. These systems typically determined the force by measuring the barrier speed or current in the motor and then calculated the force using these measurements.
Secondary obstruction detectors have also been used to detect obstructions in the path of the barrier. For instance, infrared (IR) detectors and barrier edge sensors have been used to determine if an obstruction exists in the path of the barrier. Typically, if the secondary obstruction detector indicated that an obstruction was present, the downward movement of the barrier was halted and then reversed in previous systems.
As system components age and are subjected to various environmental conditions and the system is not properly maintained, errors in the operation of previous systems may occur. For instance, if force measurements are made, the measured force may exceed the threshold value, but the door may not be encountering a real obstruction. In this case, the downward movement of the door would be reversed even though there was no actual obstruction present in the path of the barrier. For example, a nuisance such as sand or dirt maybe present in the guiding apparatus of the door path. In other examples, the door may have not been lubricated or may have worn parts. In summary, present systems are not capable of adapting their performance over time to determine if a real obstruction exists or whether the barrier reversal was caused by a nuisance or mistake.